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Hall KW , Sirk TW , Percec S , Klein ML , Shinoda W
Monodisperse Polymer Melts Crystallize via Structurally Polydisperse Nanoscale Clusters: Insights from Polyethylene
Polymers (Basel). 2020 Feb 14;12(2)
PMID: 32074962    PMCID: PMC7077701    URL: https://www.ncbi.nlm.nih.gov/pubmed/32074962
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This study demonstrates that monodisperse entangled polymer melts crystallize via the formation of nanoscale nascent polymer crystals (i.e., nuclei) that exhibit substantial variability in terms of their constituent crystalline polymer chain segments (stems). More specifically, large-scale coarse-grain molecular simulations are used to quantify the evolution of stem length distributions and their properties during the formation of polymer nuclei in supercooled prototypical polyethylene melts. Stems can adopt a range of lengths within an individual nucleus (e.g., approximately 1-10 nm) while two nuclei of comparable size can have markedly different stem distributions. As such, the attainment of chemically monodisperse polymer specimens is not sufficient to achieve physical uniformity and consistency. Furthermore, stem length distributions and their evolution indicate that polymer crystal nucleation (i.e., the initial emergence of a nascent crystal) is phenomenologically distinct from crystal growth. These results highlight that the tailoring of polymeric materials requires strategies for controlling polymer crystal nucleation and growth at the nanoscale.
2073-4360 Hall, Kyle Wm Orcid: 0000-0003-1611-7812 Sirk, Timothy W Orcid: 0000-0002-1105-4931 Percec, Simona Klein, Michael L Shinoda, Wataru Orcid: 0000-0002-3388-9227 W911NF-16-2-0189/Army Research Laboratory W911NF-18-9-0269/Army Research Laboratory Journal Article Switzerland Polymers (Basel). 2020 Feb 14;12(2). pii: polym12020447. doi: 10.3390/polym12020447.